The subject matter disclosed herein generally relates to propellers for fixed wing aircraft, rotary wing aircraft and the like. More specifically, the present disclosure relates to lightweight propeller blade construction.
Modern propeller blades typically incorporate composite materials to reduce weight and enhance performance. However, the inboard portion of the blade, called the retention member 104, is typically made of steel. Shown in FIG. 11 is an example of a present composite propeller blade 100. The blade 100 includes an outer portion or spar 102 formed of lightweight composite materials. A retention member 104 is formed from a metal, such as steel, aluminum, or titanium, and includes features to interact with bearings 106 at a propeller hub 108. The bearings 106 react the blade centrifugal and bending loads, while allowing the blade 100 to change pitch. The steel retention member 104 is rather long to accommodate a bond joint 110 with the spar 102, at which the retention member 104 extends inside of the spar 102, and is secured to the spar 102. Due to the features described above, the weight of the steel retention member 104 can be about ⅓ the total blade weight.